It has become increasingly important to accurately space the insulated multiple conductors with respect to each other and laminated flat ribbon cable has increasingly come into use for this purpose. Precise control of electrical characteristics such as impedance, capacitance, cross talk and attenuation, especially important in digital data, and signal, transmission is thereby achieved. Both controlled regular spacing and controlled irregular spacing, of multiple conductors in ribbon cable form has been achieved, in the prior art, by laminating the accurately spaced insulated (or uninsulated multiple conductors between thin plastic film, such as 5 mil polyvinyl chloride (pvc) film or 5 mil Teflon* film. FNT *Teflon is a registered trademark of E. I duPont de Nemours, Wilmington, Del.
Multiple pairs of insulated wires have also been accurately spaced, in ribbon cable, by laminating multiple pairs of twisted wire between thin plastic film, the twisted pairs being first laid onto a lower plastic film and encapsulated and accurately oriented by an upper plastic film laminated to the lower film. The use of twisted pairs of multi-conductor cable is of great importance in the field of communications, data processing and other applications where cross-talk in signal transmission must be kept to a minimum. The laminated, twisted pair, multi-conductor ribbon cable of the prior art has, however, one material drawback, namely, that present, standard, terminating techniques require that after the twisted pairs which are to be terminated have been separated from the laminate, the ends of each pair must then be untwisted manually, or with the aid of a special pliers or other tools. The separation procedure is time consuming and becomes impractical when dealing with large amounts of termination points or when it may be preferred to terminate the ends of such multi-conductor laminated ribbon cable onto an Insulation Displacement Connector (IDC), for an IDC requires great accuracy in the spacing of the ends of the multi-conductor cable which are to be terminated thereon.
The invention is therefore directed towards an improved laminated multi-conductor ribbon cable, having a plurality of twisted pairs of cables laminated therein, which overcomes the just-mentioned time-consuming problem of untwisting the cable for termination purposes.